/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package com.dili.dd.flume.plugin.exthdfs;

import com.google.common.base.Preconditions;
import org.apache.flume.Context;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SequenceFileSerializerFactory {

    private static final Logger logger =
            LoggerFactory.getLogger(SequenceFileSerializerFactory.class);

    /**
     * {@link org.apache.flume.Context} prefix
     */
    static final String CTX_PREFIX = "writeFormat.";

    @SuppressWarnings("unchecked")
    static SequenceFileSerializer getSerializer(String formatType,
                                                Context context) {

        Preconditions.checkNotNull(formatType,
                "serialize type must not be null");

        // try to find builder class in enum of known formatters
        SequenceFileSerializerType type;
        try {
            type = SequenceFileSerializerType.valueOf(formatType);
        } catch (IllegalArgumentException e) {
            logger.debug("Not in enum, loading builder class: {}", formatType);
            type = SequenceFileSerializerType.Other;
        }
        Class<? extends SequenceFileSerializer.Builder> builderClass =
                type.getBuilderClass();

        // handle the case where they have specified their own builder in the config
        if (builderClass == null) {
            try {
                Class c = Class.forName(formatType);
                if (c != null && SequenceFileSerializer.Builder.class.isAssignableFrom(c)) {
                    builderClass = (Class<? extends SequenceFileSerializer.Builder>) c;
                } else {
                    logger.error("Unable to instantiate Builder from {}", formatType);
                    return null;
                }
            } catch (ClassNotFoundException ex) {
                logger.error("Class not found: " + formatType, ex);
                return null;
            } catch (ClassCastException ex) {
                logger.error("Class does not extend " +
                        SequenceFileSerializer.Builder.class.getCanonicalName() + ": " +
                        formatType, ex);
                return null;
            }
        }

        // build the builder
        SequenceFileSerializer.Builder builder;
        try {
            builder = builderClass.newInstance();
        } catch (InstantiationException ex) {
            logger.error("Cannot instantiate builder: " + formatType, ex);
            return null;
        } catch (IllegalAccessException ex) {
            logger.error("Cannot instantiate builder: " + formatType, ex);
            return null;
        }

        return builder.build(context);
    }

}
